Measurement incompatibility in Bayesian multiparameter quantum estimation

Fuente: arXiv
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Hauptverfasser: Albarelli, Francesco, Branford, Dominic, Rubio, Jesús
Format: Preprint
Veröffentlicht: 2025
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author Albarelli, Francesco
Branford, Dominic
Rubio, Jesús
author_facet Albarelli, Francesco
Branford, Dominic
Rubio, Jesús
contents We present a comprehensive and pedagogical formulation of Bayesian multiparameter quantum estimation. Within this framework, we analyse the role of measurement incompatibility and establish its quantitative effect on attainable precision. We achieve this by deriving upper bounds based on the pretty good measurement -- a notion from hypothesis testing -- combined with the evaluation of the Nagaoka--Hayashi lower bound. In general, we prove that, as in the many-copy regime of local estimation theory, incompatibility can at most double the minimum loss relative to the idealised scenario in which individually optimal measurements are assumed jointly implementable. Therefore, in practical situations, the latter may provide a sufficient and computationally efficient benchmark without solving the full optimisation problem. Our results, which we illustrate through applications of discrete phase imaging, phase and dephasing estimation, and qubit sensing, provide analytical and numerical tools for assessing ultimate precision limits and the role of measurement incompatibility in Bayesian multiparameter quantum metrology, including an open-source package for all the bounds discussed here.
format Preprint
id arxiv_https___arxiv_org_abs_2511_16645
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Measurement incompatibility in Bayesian multiparameter quantum estimation
Albarelli, Francesco
Branford, Dominic
Rubio, Jesús
Quantum Physics
We present a comprehensive and pedagogical formulation of Bayesian multiparameter quantum estimation. Within this framework, we analyse the role of measurement incompatibility and establish its quantitative effect on attainable precision. We achieve this by deriving upper bounds based on the pretty good measurement -- a notion from hypothesis testing -- combined with the evaluation of the Nagaoka--Hayashi lower bound. In general, we prove that, as in the many-copy regime of local estimation theory, incompatibility can at most double the minimum loss relative to the idealised scenario in which individually optimal measurements are assumed jointly implementable. Therefore, in practical situations, the latter may provide a sufficient and computationally efficient benchmark without solving the full optimisation problem. Our results, which we illustrate through applications of discrete phase imaging, phase and dephasing estimation, and qubit sensing, provide analytical and numerical tools for assessing ultimate precision limits and the role of measurement incompatibility in Bayesian multiparameter quantum metrology, including an open-source package for all the bounds discussed here.
title Measurement incompatibility in Bayesian multiparameter quantum estimation
topic Quantum Physics
url https://arxiv.org/abs/2511.16645